image: Reorganize into several sub-modules

src/widgets/image/scrollable.rs

@@ -0,0 +1,118 @@
+// Copyright (c) 2023 Sophie Herold
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use super::*;
+
+impl ScrollableImpl for imp::LpImage {}
+
+impl imp::LpImage {
+    pub fn set_hadjustment(&self, hadjustment: Option<gtk::Adjustment>) {
+        let obj = self.obj();
+
+        let adjustment = hadjustment.unwrap_or_default();
+
+        adjustment.connect_value_changed(glib::clone!(@weak obj => move |_| {
+            obj.request_tiles();
+            obj.queue_draw();
+        }));
+
+        self.hadjustment.replace(adjustment);
+        obj.configure_adjustments();
+    }
+
+    pub fn set_vadjustment(&self, vadjustment: Option<gtk::Adjustment>) {
+        let obj = self.obj();
+
+        let adjustment = vadjustment.unwrap_or_default();
+
+        adjustment.connect_value_changed(glib::clone!(@weak  obj => move |_| {
+            obj.request_tiles();
+            obj.queue_draw();
+        }));
+
+        self.vadjustment.replace(adjustment);
+        obj.configure_adjustments();
+    }
+
+    pub fn set_ignore_scroll_policy(&self, scroll_policy: gtk::ScrollablePolicy) {
+        log::error!("Ignored setting new scroll policy {scroll_policy:?}");
+    }
+
+    pub fn scroll_policy(&self) -> gtk::ScrollablePolicy {
+        gtk::ScrollablePolicy::Minimum
+    }
+}
+
+impl LpImage {
+    /// Configure scrollbars for current situation
+    pub(super) fn configure_adjustments(&self) {
+        let hadjustment = self.hadjustment();
+        // round to application pixels to avoid tiny rounding errors from zoom
+        let content_width = self.round_f64(self.image_displayed_width());
+        let widget_width = self.widget_width();
+
+        hadjustment.configure(
+            // value
+            hadjustment.value().clamp(0., self.max_hadjustment_value()),
+            // lower
+            0.,
+            // upper
+            content_width,
+            // arrow button and shortcut step
+            widget_width * 0.1,
+            // page up/down step
+            widget_width * 0.9,
+            // page size
+            f64::min(widget_width, content_width),
+        );
+
+        let vadjustment = self.vadjustment();
+        // round to application pixels to avoid tiny rounding errors from zoom
+        let content_height = self.round_f64(self.image_displayed_height());
+        let widget_height = self.widget_height();
+
+        vadjustment.configure(
+            vadjustment.value().clamp(0., self.max_vadjustment_value()),
+            // lower
+            0.,
+            // upper
+            content_height,
+            // arrow button and shortcut step
+            widget_height * 0.1,
+            // page up/down step
+            widget_height * 0.9,
+            // page_size
+            f64::min(widget_height, content_height),
+        );
+    }
+
+    pub fn max_hadjustment_value(&self) -> f64 {
+        f64::max(self.image_displayed_width() - self.widget_width(), 0.)
+    }
+
+    pub fn max_vadjustment_value(&self) -> f64 {
+        f64::max(self.image_displayed_height() - self.widget_height(), 0.)
+    }
+
+    pub fn is_hscrollable(&self) -> bool {
+        self.max_hadjustment_value() != 0.
+    }
+
+    pub fn is_vscrollable(&self) -> bool {
+        self.max_vadjustment_value() != 0.
+    }
+}